Pump structure



Aug. 28, 1945. J. F. HoFFER PUMP STRUCTURE Filed Feb.' 9. 194e 2 Sheets-Sheet 1 mm Y W @www QR m. n 1+ N :Warm

' Patented Aug. 28,1945 l FFlcE PUMP STRUCTURE James F. Hofi'er, Detroit, Mich., assignor toEx- Ceil-O Corporation, Detroit, Mich., a corporation of Michigan Application February 9, 1942, serial No. 429,998

claims. (cl. 10a-.44)

The present invention relates to improvements in pumps and has particular reference to a new and improved pump structure which is especially suited for use with a delivery pump for supplying fuel in metered charges at a relatively high pressure to an internal combustion engine.

An object ofv the invention is to provide a new and improved transfer pump unit comprising a primary pump for transferring fuel to a. delivery pump and having a pressure controlled plunger, which plunger serves also as the pumping element of an auxiliary pump for removing fuel leaking from the delivery pump.

Further objects and advantages will become apparent as the descriptionproceeds.

In the accompanying' drawings,

Figure l ls a `fragmentary vertical sectional view of a pump structure embodying the features' of my invention, part of the structure being shown in side elevation. 1

Fig. 2 is a top plan view of a transfer pump unit forming part of the structure.

1'lg. 3 is a side elevation of the transfer pump u t.

Fig. 4 is s. left-end elevation. Fig. 5 ls a right-end elevation. Fig. 6 is a transverse vertical sectional view taken along line 8 6 of Fig. 1.

cember 9, 1941. In the present instance, the fuel delivery pump I comprises a housing 5 adapted to be mounted'on a suitable support, such as the crank case of an internal combustion engine. A cylinder body 6 is mounted in one end of the housing 5, and lsformed with a central bore 7 and with a plurality of parallel pump cylinders 8 arranged in angularly spaced relation about the bore. A plurality of pump pistons 9 are reciprocably disposed in the cylinders 8, and are urged outwardly by compression springs I0. I

Mounted in the other end ofthe housing 5 is a driving mechanism for eecting reciprocation of the pistons 9 in uniformly timed sequence. This mechanism comprises a plurality of actuating plungers or tappets Il reciprocably guided in the housing 5, and disposed in axial alinement, and in end abutting engagement, respectively with the pistons 9.l A rotary swash plate I 2 coacts with the plungers il, and is operable by a central drive shaft I3 in axial alinement with the vbore 1. The pressure ends of the pump cylinders 8 open respectively through outlet check valves i4 to a plurality of delivery lines i5, and have lndividual inlet ports IB opening, in a common transverse plane from the bore l. A groove il is formed in the periphery of the bore 1, and is open to an inlet passage IB Aconnected to a low ,Fig. 7 is a fragmentary detail sectional view f taken along line 1-1 of Fig. 6.

Fig. 8 is an enlarged sectional view through a valve forming part of the transfer pump unit.

Fig. 9 is a fragmentary detail sectional view taken along line 9-9 of Fig. 6. L l

Referring more particularly to the drawings, the pump structure. illustrating the invention, comprises generally a delivery pump i for discharging fiuid under a relatively high pressure, and a transfer pump unit, including a primary pump 2 for supplying or transferring fluid under a relatively low pressure to the inlet of the delivery pump l, and two auxiliary pumps I and 4 respectively for scavenging accumulated' fluid leaking from the pumping means of the delivery pump, and accumulated lubricant leaking from or circulating through the driving mechanism of the delivery pump. 'I'he pumps 2, l and 4 are combined in a unit assembly, and are operated in' timed relation to each other and to the delivery pump l.

The high pressure delivery pump i may be of any desired form or type, and vis herein disclosed for purposes of illustration as an adjustable metering and distributing 'fuel pump like that disclosed in mylPatent No. 2,265,232, issued Depressure iiuid supply line i9. Mounted in the bore 1 is a rotary valve member 20 having a relief area 2i adapted to eifect communication between the ports i6 and the groove Il, and having a narrow land area 22 movable successively across the ports to close each port during a predeterf mined portion of the working stroke of the assoclatedpiston 9. The valve member 20 is operatively connected to the shaft i3 for rotation thereby in timed relation to the reciprocation of -the pistons 9.

In the operation. of the delivery pump iI predetermined quantities of fluid, such as liquid fuel, are discharged under a relatively high pressure and in timed sequence to the delivery lines l5. Any fuel leaking from the closed ends of the cylinders 8 along the pistons 9, and from the groove ii inwardly along the valve member 20, will pass into the left-end portion of the interior of a housing 5 between the cylinder body 6 and the ipump driving mechanism. Similarly, any lubricant leaking inwardly along the plungers li will also Dass into the right-end portion of the interior of the housing 5 between the cylinder body t and the driving mechanism.

The transfer pump unit comprises a generally rectangular body 23 which is normally disposed in a horizontal position, and which is formed, at the top with a fiat marginal flange or plate 24 adapted to be secured in position against a mounting surface 25 on the underside of the delivery pump housing 5. Preferably, the plate 24 is located by a plurality of diagonally spaced dowel pins 26 and is secured to the housing 5 by four corner bolts 21. A marginal gasket 28 is inserted between the housing and the plate 24 to obtain a fluid-tight connection.

The bottom wall of the pump housing 5, intermediate the pumping unit and the drive mechanism, is formed with an opening 29 which is cir' cumscribed by the marginal surface 25, and which hence is closed by the plate 24 of th'e body 23. The top face of the plate 24 is recessed to form two open reservoirs or sumps 30 and 3I which are arranged respectively to collect fuel and lubricant leaking from the pumping unit and the drive mechanism into the housing 5 and then dripping or draining through the opening. 29. A transverse rib or dam 32, rising to the top level of the plate 24, separates the sumps 30 and 3i to prevent intermingling of the leakage fuel and lubricant. The fluids collecting in the sumps 38 and 3l are removed by the auxiliary pumps 3 and 4 as is hereinafter more fully described.

The primary pump 2, for transferring fuel to the supply line I9 of the pump I, comprises a longitudinal medial cylinder 33 formed in and opening through the body 23, One end of the cylinder is closed by a plug 34, and the other end is formed with acounterbore 35 constituting an auxiliary cylinder and defining an outwardly facing annular stop shoulder 38. A sleeve nut 31 is threaded into the outer end of the counterbore 35 to close the latter.

Opening respectively to opposite sides of the cylinder 33 in a common transverse plane intermediate its ends are an inlet port 38 and an outlet port 39. The inlet port 38 is connected through an inlet check valve 48 with a supply passage 4| which extends to one end of the body 23. A suction line 42 leading from a suitable .source of fuel, such as a supply tank (not shown) is detachably connected to the body 23 and communicates with the outer endof the passage 4|.

The inlet check valve 40 comprises a valve passage 43 intersecting the supply passage 4I and opening vertically through a. valve seat 44 to a valve chamber 45. The chamber is closed at the top by a screw plug 48, and connects with the port 38. A suitable valve member 41 is slidably guided in the plug 48, and is normally urged by a compression spring 48 into engagement with the seat 44.

.Formed in the body 23 and connected to the inner end of the supply passage 4I is a large bore 49 which serves as a surge chamber or accumulator. The outer end of the bore 49 is closed by a plug 50, and the two plugs 34 and 50 are secured in position by a lock screw 5I.

The outlet port 39 is connected through an outlet check valve 52 to a delivery passage 53 which extends to one end of the body 23, and is connected with the supply line I9 leading to the inlet of the pump I. The outlet check valve 52 comprises a valve chamber 54 formed in one side The chamber 54 opens through a valve seat 58 to `the outlet port 39, and intersects the delivery passage 53. A suitable valve member 51, slidably guided in the screw plug 55, is normally urged into engagement with the seat 58 by a coiled compression spring 58.

of the body 23, and closed by a screw plug 55.

A relief valve 58 is connected to the chamber 54 to dissipate excessive pressures in the event of abnormal operating conditions. The -valve 89 has an inlet passage 89 controlled by an adjustable spring-seated ball valve member 8i, and has an outlet passage 82 opening to the sump 38,

Reciprocably mounted in the cylinder 33 intermediate its ends is a pump piston 83. Preferably, the piston 83 is driven by the delivery pump I in timed relation to the pistons 9. The drive connection comprises a vertical pin 84 which is formed at the upper end with a sleeve 85 fitting snugly about and rigidly locked to the lowermost actuating plunger or tappet II. 'Ihe lower end of the pin 84 extends with a close flt inw a diametrical bore 88 in the piston 83 substantially midway of its ends. A relatively large vertical bore 81 in the body 23 opens downwardly from the sump 38, and fully intersects the cylinder 33 to permit the drive connection and to accommodate the translation of the pin 84. The bore 81 is somewhat larger in diameter than the cylinder 33, and hence provides vertical passages 88 at opposite sides of the piston 83 adapted to receive fuel from the sump 30.

One end of the piston 83, having an end face 89, constitutes the active end in the primary pump 2. At the end of the pressure stroke, the piston face 89 advances substantially to the plane of the inlet and outlet ports 38 and 39. To prevent blocking of these ports, suitable arcuate grooves 19 are formed in opposite sides of the piston 83 at the end face 88. V

In operation, movement of the piston 83 on its outward stroke away from the ports 3 8 and 39 will cause the flow of fuel from the supply tank through the inlet valve 48 in whatever amount is required to fill the cylinder 33, and movement of the piston in the reverse direction on the pressure stroke will cause the discharge of fuel under pressure through the outlet check valve 52 to the supply line I9 for the delivery pump I.

Apressure control plunger 1I is reciprocable in the left end of the cylinder 33 in opposed relation to the active end of the piston 83, and coacts therewith to define the pressure chamber of the pump 2. The plunger has an enlarged peripheral flange or head 12 freely reciprocable in the auxiliary cylinder 35, and adapted to limit inward movement by engagement with the stop 38. The plunger 1I is urged inwardly by spring pressure, and in effect constitutes a yieldable end wall of the pump pressure chamber. In the present instance, the spring means comprises two coaxial compression springs 13 and 14 which at one end bear against a flange 15 on a pilot sleeve 18 seated in the sleeve nut 31, and which at the other end engage in a centering recess 11 in the head 12.

vI'he displacement of the piston 83 is normally equal to and preferably in excess of the maximum requirements of the associated fuel injection pump I, and the pressure control plunger 1I is operableautomatically to vary the volume of fuel actually delivered in accordance with the existing requirements at a predetermined maximum pressure. If at any time the full displacement of the piston 83 is required, the springs 13 and 14 will maintain the head 12 against the stop 38 to constrain the plunger 1I against movement out of its innermost position. In the event that the full displacement of the piston 53 is not required, the pressure in the cylinder 33 will cause the plunger 1I to move outwardly during the pressure stroke of-the lcharged through the valve inward movement piston, so that only part of the displacement of-the piston will be dis- 82. In the subsequent suction stroke of the piston 33, `the plunger 1| will moveinwardly to maintain the fuel inthe cylinder 33 under a predetermined maximum discharge pressure until the head 12 again engagesI the stop 39, and thereafter fuel in an amount suillcient to refill the cylinder will enter through the valve 40. If no fuelis required by the delivery pump l, the plunger 1| will travel in synchronism with the piston 63, thereby resulting in zero delivery. Consequently, the pump 2" is selfrelieving to supply the demands of the delivery pump from zero to maximumat the maximum delivery pressure.

"The auxiliary pump 3 utilizes'the counterbore 35 as a cylinder, and the plunger 1| asa piston,

and is operable 'to take leakage fuel from the sump 30 and. transfer it to the source of supply for the delivery Vpump I or to some other con-` venient place. The pump 3 has an inlet passage `18 which connects at one end with thebottom of the bore 61,' and which opens at the other end through aport 19 to the outer end portion of lthe cylinder 33. The piston 1| serves to uncover the port 19 when in its innermost position inthe cylinder 33, and to close theuport upon initial suction'stroke for the pump 2 being the pressure piston 63.at the end of the suction stroke and is closed in the initial movement of the piston on the pressure stroke. The cylinder 9| also has an outllet-passage 93, whlch opens through the body 23 to the top face of the flange 24 in registration with apassage 94 through the housing 5 for returning the discharged lubricant to the crank case of the engine. The gasket 28 between the body 5 of the pumpi and the mounting plate 24 of vthe pump movement out of this position. In the present instance, the piston 1| is formed beneath the head 12 with a peripheral groove 80 adapted to communicate with the port 19 when the head 12 engages the stop 38, and with a plurality of apertures 8| opening from the groove 80 through the head 12 to complete the ow connection to the cylinder 35.'

The pump 3 has an outlet check valve 82 mounted in the sleeve 16 and adapted for connection to a return line 83. The valve 82 may be of any suitable form, and in the present instance (see Fig. 8) comprises a body having a valve passage 85 with member 81 is normally urged against the seat 86 by ,a coiled compression spring 88 which is confined in the body 89. Preferably, filtering elements 90 are mounted in opposite ends of the valve body 84.

,In operation, it will be seen that the plunger 1| performs the dual function of controlling the effective displacement of the pump l2 at a given maximum' pressure in accordance with the rea seat 88. A ball -valve- 84 by a tubular pilot sleeve 2 is suitably apertured to establish communicatin between the passages 93 and 94. Inserted in the passage 93 is an outlet check valve unit 95 of the same type as the valve 82.

In operation, the piston 63 uncovers Athe inlet port 92 at the end of the suction stroke in the cylinder 9| to permit the entry of accumulating lubricating oil fromv the sump 3|. On the pressure stroke of the pump 4,A the piston 63 will discharge the lubricant from the cylinder 9| through the passages 93 and 94 and valve 95 to the 1engine crank case.

The dam 32 prevents the fuel and lubricant collecting respectively in the sumps 3.0 and 3| normally from intermin-gling. If-either of the auxiliary pumps 3'or 4 should fail to operatebroperly to transfer kthe .fluid collecting in the corresponding sumps, the associated sump would `fil1 up and 4 the fluid therein would overflow the" dam 32.

quirements of the pump and at `the same time y piston of the pump 3. Upon of the piston 1| to the right into engagement with the stop 39,' a suction is created in the cylinder 35, and the port 19 is opened to admit fuel from the sump 30. Upon outward movement of the piston 1|, the port 19 is cut on', and thereafter the fuel in the cylinder 33 is compressed and discharged through the valve 82 into the line 83 for return to the fuel supply tank. While the pump 3 .is operative only as an incident to the reciprocation of the plunger 1|, the latter is reciprocated enough in the normal operation of the pump structure to remove all the leakage fuel accumulating in the sump 30.

The auxiliary pump 4, for, removing lubricant leaking from the housing 5` and collecting into the sump 3|, utilizes the right end of piston 63 as the pumping element and the closed end of the cylinder 33 as the cylinder or pressure chamber 9|. Thus, the piston 83 is of tl'ie double ofA serving as the acting type, its pressure stroke for the pump 'il Means is provided for indicating such abnormal condition of operation, and in the present in.

stance, this means .comprises two' longitudinal grooves 96 formed in the top of the dam at opposite sdes of the vertical bore 61, and arranged to catch any overflow from either sump. The grooves 96 are connected through vertical downfiow passages 91 to two relatively large bores 99 formedin opposite sides of the body 23. Suitable lters 99 are mounted in theI bores 98. In the event oi?l anyoverfiow, fluid will pass to the filters 99, and indicate that atleast one of the pumps 3 and 4 is notoperating properly. From.

the character of the fluid noticeable at the filters 9 9, the offending pump can be identified.

Means is also provided for reciprocating the plunger 1| manually to prime the pump with- 'out cranking the engine when the pump is idle.

The means for this purpose comprises an actuating plunger |00 which extends reciprocably through a bore |0| in theI body 23. One end of the plunger |00 projects for engagement with the head 12, and the other end projects from l the body 23 for engagement by the rounded free end of a lever arm |02 nxed on a rock shaft |03. vThe latter is journaled in parallel spaced lugs or webs |04 r integral with one end of the body 23. A hand lever |05 may be fixed on the shaft |03 for vactuating the latter. Normally, the springs 13 and 14 acting through the head 12 tend to move the piston 1| in its suctlonstroke, and to swing the lever |05 to the right. Additional spring means may, however, be provided for insuring movement of the lever |05 to the right independently of the piston 1|. 'I'his spring means comprises a plunger |06 reciprocable in a bore |01 parallel to the bore |0| in the body 23, and urged outwardly by a coiled compression spring. |08 into engagement with the lever arm |02. By alternately actuating the hand lever |03, first in one direction against the action of the springs 13, 14 and |08, and then in the reverse direction, pumping reciprocation will be imparted to the piston 1| independentlysaid piston out oi said end position in opposition to said spring means, a plunger extending reciprocably through said body for actuating said piston in opposition to said spring means, a rock shaft journaled in said body, a lever arm on said shaft and engaging one end of said plunger to actuate the latter, and supplemental cember l, 1944, the presentapplication being directed to the type of pump exempliiled by the l' pump 3.

spring means mounted on said body and acting against said lever arm in a direction to release l said plunger.

I claim as my invention: i. A pump structure comprising, in combination, a body having a cylinder, said body being formed in the top with a sump and with a bore opening from said sump of greater width than the diameter of the cylinder to and intersecting said cylinder, a piston reciprocable in said cylinder, drive means for said piston extending. outwardly through said bore, means for supplying fluid to said cylinder during the suction stroke of said piston and /for discharging iiuid from said cylinder during the pressure stroke of said piston, a pressure control plunger reciprocable in said cylinder independently of said piston and constituting an end Wall thereof in opposed relation to said piston, said control plunger being movable outwardly solely in response to pressure fluid in said cylinder, spring means for urging said plunger inwardly with a predetermined pressure, and means utilizing said control plunger as an auxiliary piston for transferring fluid from said sump to a point external of vsaid cylinder.

4. A pump structure comprising, in combination, a body formed with a horizontal longitudinal cylinder and an alined auxiliary cylinder and with a sump in the top and a recess opening downwardly from said sump and intersecting said cylinder, a piston reciprocable in said cylinder, said recess deilnlng downtlow passages at opposite sides of said piston, a plunger reciprocable in said cylinder and having an apertured head reciprocable in said auxiliary cylinder, means for 'supplying iluid to and from said cylinder between said plunger and said piston, spring means acting on said plunger in opposition to the pressure in said cylinder, an inlet passage opening from said recess and having an inlet port opening to said cylinder beneath said head, said plunger having a groove beneath said head normally opento said port and adapted to close 'said port upon outward movement of said plunger against said spring means, and outlet valve means opening from said auxiliary cylinder.

2. A pump structure comprising, in combination, a cylinder body formed with a cylinder, a piston reciprocable in said cylinder, inlet valve means and outlet valve means opening to and from said cylinder, spring means tending to urge i said piston toward and into one end position,

fluid pressure means for periodically actuating said piston out of said end position in opposition to said spring means, a plunger extending reciprocably through said body for actuating said piston in opposition to said spring means, a rock shaft journaled in said body, and a lever arm on said shaft and engaging one end of said plunger to actuate the latter.

3. A pump structure comprising, in combination, a cylinder body formed with a cylinder, a piston reciprocable in said cylinder, inlet valve means and outlet valve means opening to and y from said cylinder, spring means tending to urge said piston toward and into one end position, fluid pressure means for periodically actuating 5. A pump structure comprising, in combination, a body formed with a horizontal longitudinal cylinder and an alined auxiliary cylinder and iluid supply openings and a recess intersecting said cylinder, a piston reciprocable in said cylinder, said recess defining down-now passages at opposite sides of said piston, a plunger reciprocable in said cylinder and having an apertured head reciprocable in said auxiliary cylinder, means for supplying fluid to and from said cylinder between said plunger and said piston, spring means acting on said plunger in opposition to the pressure in said cylinder, an inlet pasage opening from said recess and having an inlet port opening to said cylinder beneath said head, said plunger having a groove beneath said head normally open to said port and adapted to close said port upon outward movement of said plunger against said spring means, and outlet valve means opening from said auxiliary cylinder.

. JAMES F. KOFFER. 

